The present invention relates to a structure for supporting a load and, more particularly, to a durable skid of recyclable paperboard.
Wood, metal, plastic, and paper are frequently manufactured into load supporting devices. One of the least expensive and most easily manipulated materials is paper. Various structures, such as corrugated paperboard, take advantage of the strength of paper by properly forming items to exploit paper's inherent characteristics. Specifically, a strip of corrugated paperboard is readily bent traversely of its plane, however, the strip has considerable tensile and compressive strength when subjected to edgewise pressure.
A supporting structure, such as a shelf, can be made from paper. Typically, the paper or corrugated paperboard is cut to lay across a plurality of brackets. However, multiple layers of the paper or corrugated paperboard must be built-up to provide the desired strength. Unfortunately, this built up mass adds weight, size and cost to the end product and places the load traverse to the plane of the shelf.
Another approach is to take advantage of the tensile and compressive strength of paper or corrugated paperboard under edgewise pressure. However, while strength is considerably increased, in a support structure resulting from a solid block of paper or from multiple layers of corrugated paperboard secured together with their respective edges turned toward the direction of the load, the weight and cost of the product is unacceptable. For example, multiple layers of triple-wall paperboard comprising three corrugated or fluted layers of paper placed between and secured to four planar paperboard layers can be secured together and used to exploit the edgewise strength of the paperboard. See, for example, U.S. Pat. No. 3,199,764. However, the same high density, weight, and cost drawbacks exist.
Various support structures for supporting a load have taken advantage of the relative low cost and pliable nature of paper. However, a less dense, higher strength, and more rigid structure for supporting a load is needed while maintaining low cost and light weight.
For example, pallets and skids of corrugated paperboard have gained considerable popularity within the industry for use in transporting various goods. In comparison to wooden pallets, corrugated paperboard, pallets and skids are lighter to transport and less expensive to make. Additionally, paperboard skids can be shredded for disposal, recycled to reduce refuse costs, and nonreturnable to eliminate return transportation costs. Corrugated paperboard skids are even lighter and less expensive than paperboard pallets. Since the skids do not have bottom slats they occupy less space in storage and shipping due to the advantage offered by alternate stacking.
U.S. Pat. No. 4,936,229 discloses a pallet having two flat sheets of cardboard separated by a plurality of individual layers of cardboard runners, which are adhesively connected to the sheets. In this design, strength and rigidity are given up in exchange for simplicity and cost savings.
A more intricate design is disclosed in U.S. Pat. No. 4,979,446. The '446 patent uses sheets of corrugated paperboard with holes, scores, and creases to make each stringer. The sheets are intricately folded to make a stringer having a vertically oriented core surrounded by alternating vertical and horizontal panels, thereby encasing most of the otherwise exposed corrugated fluting. The stringers interconnect to form a pallet. While the latter design is stronger and more rigid than the former, the resulting pallet is more complicated and costly.
In light of the foregoing, there is a need for a support structure which has the desired strength and rigidity to support a load, yet is relatively light and inexpensive. In particular, there is a need for a corrugated skid which has the necessary strength and rigidity to transport bulk goods, yet is relatively simple in design and correspondingly less costly to manufacture and having less weight to transport.